遮断機【しゃだんき】
(railway) crossing gate, barrier (at a toll booth, parking lot, etc.)
遮断器【しゃだんき】
circuit breaker
遮断【しゃだん】
isolation, cut off, blockade, quarantine, interception, deprivation
遮る【さえぎる】
to interrupt, to obstruct (a view, someone's way, etc.), to block (light, wind, etc.), to intercept, to cut off